[Discuss-gnuradio] Problem with capture playout WBX daughterboard USRP N210

[Bastien Auneau]

Hi All

Using USRP N 210, WBX board, GPSDO, UHD 3.2.2, under Windows 7

We want to use the example scripts to capture then playout a signal we
get from the air (satellite link with bursts). We proceed as follow :
1. capture using rx_samples_to_file.exe --type short --rate 10000000
--freq 1057232000 --gain 10

2. playout the newly captured file
tx_samples_from_file.exe --type short --rate 10000000 --freq 1057232000
--gain 2

3. Using a spectrum analyzer, we expect to see similar things when
looking at signal from air (few small carriers, bursty), than when
looking at USRP played out signal.

But the USRP only output an around 2.5 MHz carrier, which does not
contains the burst of the original carrier (looking on live signal the
centered carrier constantly goes up and down). The carrier is extremely
steady during all the playout time. Also, the doc
(http://www.ettus.com/downloads/ettus_daughterboards.pdf) specifies
30MHz bandwidth, why can't we see the same bandwidth from played out
signal than from original signal ?

Also, we use the rx/tx port of the WBX board to capture then to playout

Regards
Bastien